The present invention concerns improved fuel compositions. More particularly, it relates to diesel fuel compositions having improved wear resistance.
Internal combustion engines, particularly diesel engines are susceptible to wear in the upper cylinder region. It is believed that the majority of wear occurring in the upper cylinder is caused by the upward motion of the piston. While lubricating oils prevent wear on the downward stroke, the lubricating oil has no contact with the cylinder wall on the upward motion. During the upward compression stroke only the fuel is in contact with the cylinder wall and can influence its wear.
Accordingly, it is an object of the invention to provide diesel fuel having improved antiwear properties.
It is known that reaction products of a maleic compound and 2,5-dimercapto-1,3,4-thiadiazole impart antioxidant and antiwear properties to lubricating oils as described in U.S. patent application Ser. No. 07/045,652 filed May 4, 1987.
It has been now discovered that a certain group of the reaction products impart antiwear properties to diesel fuel.